Our major goal is the elucidation of the pathophysiology in infants and children with disorders of carbohydrate metabolism. This should provide a better understanding of the physiology of carbohydrate regulation as well as the developmental role of hormones and their receptors. Diet and other therapeutic modalities will be evaluated not only in treatment but also on the neurological and psychological development of the young patients. Our studies of Nesidioblastosis, Leucine Sensitivity, the Beckwith-Wiedemann Syndrome and Glycogen Storage Disease Type I have shown: (1) some of these patients have increased insulin receptors on their erythrocytes, which might explain their symptomatic hypoglycemia as an increased response of peripheral tissues to insulin. (2) Inslin receptor values on erythrocytes. Since newborns have increased insulin binding, these data indicate a decrease in the numbers ofreceptors early in extrauterine life. In preliminary studies, Diazoxide decreased the insulin receptors.